Quote from: gbyg on May 17, 2014, 09:36:28 PM

Quote from: nst6563 on May 16, 2014, 08:02:35 PM

Quote from: gtraah on May 16, 2014, 05:48:33 PM

Can someone please confirm that this mofset will work with our Grids?

http://www.ebay.com/itm/SI7456DP-Vishay-Siliconix-Mosfet-N-So-8-/130943957886?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1e7cde3b7e

Some of the specs on that part look excessive. You'll want to match the specs as closely to this as possible: https://www.dropbox.com/s/w4m5vu4k5jgopk8/qm3022m6_ubiq.pdf

It's basically a 30v N-Channel mosfet with a 7mOhm RDSon and a 76A ID@25c (Continuous current drain at 25c). You'll want to match the gate charge as close as possible as well.

I burnt out that same mosfet (3022m) and replaced it with the following: http://www.ti.com/product/CSD17552Q5A. I blew my mosfet when curiosity got the best of me and I tried to dual mine with the voltmod at 1100Mhz. Moral of the story...don't do that. Don't even think of doing it. I replaced my mosfet with the one from TI and it's back up and running but it's a little crippled. Chip 3 seems to generate some errors no matter what speed, but it still hashes and I still get around 439khs from that gridseed.

I use 39AMP ID@25C mosfet just because i couldn't find more then 39AMP. there is few pin exposed on the bottom of the board. which was isolated by thermal pad. when i swap the pad with grease, those exposed shorted with the ground. and my 12 volt was off. nothing blew. so i think this mosfet start draining the current before any other part(like FB23/24) damage. which making me think that its better to use lower amp? i am not expert on this, what you think?

Well, I don't think the seeds "require" 76A - especially in scrypt only mode, but when replacing a part you should always try to match the original specs as close as possible when we don't know the original design engineering considerations.

As for the short - I think you're lucky Wink

Shorts often don't leave components untouched - so I'd be on the lookout on that particular gridseed for any premature failure down the road.